In Fallout 3, the Lone Wanderer can encounter a downed recon craft named Theta and a dead alien. In the Mothership Zeta add-on, the Lone Wanderer can be abducted by zetans at the alien crash site and taken aboard a spaceship named Mothership Zeta.
In Fallout 4, the Sole Survivor can encounter an alien spaceship falling from the sky shortly after reaching level 20. Companions have unique commentary upon observing the crash. The crashed UFO is always located east of Oberland station. Following green bloodstains will lead the Sole Survivor to a hostile injured alien which can be looted for the alien blaster pistol.
In the Creation Club quest Over the Moon, the Sole Survivor encounters a second alien craft abducting a brahmin, along with two hostile aliens with unique weapons.
Aliens appear in Fallout 3, Fallout: New Vegas, and Fallout 76. They are mentioned in Fallout and Fallout 2.
Behind the scenes
Aliens in Fallout 3 were designed to resemble stereotypical representations of aliens known as "Roswell grays," sometimes referred to as Zeta Reticulans.[Non-game 1]
↑Skynet: "{207}{}{Skynet was conceived and developed in the year 2050. Through the use of alien technology a new thinking computer was perfected. In the year 2081, Skynet became self-aware. In 2120 Skynet was given a new set of instructions and then abandoned by the Makers.}" (WSTERM3B.MSG)
Non-game
↑The Hachiko Interview With Joel Burgess & Jeff Gardiner: Players who found the UFO also found the remains of the pilot, who looks like the old school Roswell grays for the most part. Are these the same models being used for Mothership Zeta? Will the grays be the only enemies or are there a variety of new aliens to fight side-by-side with the gray pilot witnessed in the retail game? Jeff Gardiner: "Yes, we're modeling the same basic enemy after the "Roswell grays." There are other enemies that will be uncovered as well, including alien robotics."
In the Creation Club quest Over the Moon, the Sole Survivor encounters a second alien craft abducting a brahmin, along with two hostile aliens with unique weapons.
